1. Field of the Invention
The present invention generally relates to a communication system, and in particular, to a method and system for transmitting resource allocation information in a multi-hop communication system.
2. Description of the Related Art
Provisioning of high-speed large-data transmission/reception services to Mobile Stations (MSs) is an active study area for future-generation communication systems. Particularly, use of a multi-hop scheme to increase system capacity is under serious consideration. A multi-hop communication system will be described in terms of increasing system capacity.
In the multi-hop communication system, if the channel status between a Base Station (BS) and an MS is bad, a Relay Station (RS) positioned between the BS and the MS relays signals between them. As the MS transmits and receives signals on the better one between channels provided by the BS and the RS, its capacity is increased, thereby increasing system capacity.
If two RSs exist between the BS and the MS, the BS selects an RS for signal relaying and transmits control information for the selected RS and the MS. The control information is carried in a resource allocation information message such as a DownLink-MAP (DL-MAP) or an UpLink-MAP (UL-MAP).
In general, the BS transmits to RSs a resource allocation information message without information about the selected RS. Upon receipt of the resource allocation information message, the RSs decode the message, thus acquiring control information needed for data decoding, including channel coding schemes, coding rates, and modulation schemes of entire data resources.
The RSs decode entire data bursts based on the whole decoded resource allocation information message and re-encode the resource allocation information message and the data bursts. The RSs then transmit the re-encoded resource allocation information message and the entire encoded data bursts to the MS. The MS acquires resource allocation information by decoding the resource allocation information message and recovers data intended for the MS using information about data resources allocated to the MS included in the resource allocation information.
As described above, the conventional resource allocation information message does not include RS information. Accordingly, upon receipt of the resource allocation information message, an RS decodes both the resource allocation information message and data, re-encodes them, and transmits the re-encoded resource allocation information message and data to an MS. Since even data for which direct transmission between the BS and the MS is preferable in case of a bad channel connection between the selected RS and the MS is relayed through the RS after decoding, inter-cell interference increases, resulting in a decrease in performance. Moreover, the decoding of the whole resource allocation information message causes a time delay and increases power consumption.